I. Field of the Invention
This invention pertains to article-handling apparatus and, more particularly, to an apparatus which selects an item from a first station and applies a glue to the item before depositing the glued item at a subsequent station.
II. Description of the Prior Art
In the prior art, material handling devices (commonly referred to as pick-and-place machines) are well known. These devices have many uses. For example, in the printing industry such machines remove a piece of paper from a top of a pile and transfer the sheet to a second location such as a conveyor which moves the sheet into a press or other machine. Such devices are also used in the container industry to pick coupons from a tray and place them in a desired location. Additionally, in conjunction with various glue applicators, a pick-and-place machine may select a coupon from a pile and advance the coupon past a glue applicator where it receives a metered amount of glue. The glued coupon is then placed in adhesive contact with the carton.
An example of a pick-and-place machine is shown in commonly assigned U.S. Pat. No. 4,350,466 of which I am co-inventor. This patent teaches a pick-and-place machine having four support shafts mounted for rotation about their respective axes with the axes of the support shafts circumferentially spaced about a common drive shaft and parallel to the drive shaft. As the drive shaft rotates in a given direction, each of the support shafts rotates in an opposite direction. Suction cups carried by the support shafts are in air flow communication with a common manifold with the suction cups being alternately connected to a vacuum pump and a vacuum exhaust. As can be seen from the aforesaid patent, each of the suction cups travels through a hypotrochoidal path about the axes of the drive shaft. The path has three points disposed 120.degree. apart. At these points, the suction cups are facing outwardly away from the drive shaft. Between the three outward points, the suction cups face inwardly toward the drive shaft. A coupon tray is placed adjacent one of the points and an article displacement location is adjacent another of the points. A vacuum is applied to the suction cup immediately prior to the cup attaining the point adjacent the coupon tray and the vacuum is ended when the same cup has moved to a position adjacent to the discharge point. As a result, the suction picks an article from the tray and carries it 120.degree. through the hypotrochoidal path until it reaches the discharge point at which location the vacuum is ended so that the coupon is placed in its desired position.
It is desirable to use an apparatus such as that described in U.S. Pat. No. 4,350,466 to also apply a glue to an article which has been picked up by a suction cup and is being carried to its desired location. One way to accomplish this is to have the suction cup pick up an article at one of the three points of the path and carry it to a second point at which location a glue is applied. The apparatus then carries the glued article to the third point of the path at which location the article is discharged. Accordingly, an article is carried 240.degree. about the drive shaft with 0.degree. being defined at the pick-up point, 120.degree. as the glue application point and 240.degree. as the discharge point. An unfortunate problem with such an apparatus is that the glue applied to the article is minimal and is often insufficient in amount.